Your taxes are due today.
- Network Administration in 1995!
- Chapters 9 & 10 (networking) of How Linux Works
Follow along with How Linux Works
Connect to How Linux Works and following along. Use your workstation and Pi and notebook.
Section 9.2 — Network Layer
You need to know the layers; but add the MAC layer.
What is the MAC layer address of your device? Use ifconfig.
Section 9.3 — Internet Layer
What is the MAC and network layer addresses of your device? Use the ifconfig and ip commands.
Everyone uses CIDR but evidently the Cisco exams still mention class A, B and C networks. Look at section 9.3.2 and think about using your CSCI 255 skills to determine if an IP host is on your LAN.
- 126.96.36.199/16 is the UNC Asheville network
- 188.8.131.52/24 is the UNC Asheville CSCI network
- Many (maybe most) computers are located on private networks.
- A manually configured /etc/NetworkManager/system-connections/Wired connection
Section 9.4 — Routes
- route -n
- ip route
- netstat -r
The main campus routers have routing tables with bazillions of entries.
Section 9.5 — Tools
Section 9.6 — Physical layer
Section 9.7 — Kernel networking
- ifconfig but read the details
Section 9.8–9.11 — How the network is managed
With Ubuntu, it’s NetworkManager. With Raspbian, it’s dhcpcd. Both use wpa_supplicant to handle wireless connections.
Section 9.12 — Resolving hostnames
- UNCA CS name server files
Simulate a FQDN to IP lookup using dig,but remember that your computer caches its host lookups.
Section 9.13 —
There’s no place like home.
Section 9.14 — Transport layer
- netstat -ntl
- netstat -nt
- netstat -t
- netstat -an
- sudo lsof -i :auth
You can start and accept connections from the command line.
- nc -l 3333
- nc -k -l 3333
- nc hostname 3333
- printf "GET /sysadmin HTTP/1.0\r\n\r\n" | nc www.cs.unca.edu 80
- printf "GET /sysadmin/ HTTP/1.0\r\n\r\n" | nc www.cs.unca.edu 80
Section 9.16 — DHCP
Look at the computer science DHCP configuration file.
Section 9.19 — Network Address Translation
Look at a login session to a home router.